Ultra Wideband (UWB) receivers face unique challenges in signal reception due to low signal levels, high signal frequencies, large bandwidths, and the like associated with the UWB signal environment. In particular, given that, for reasons understood in the art, UWB receivers are required to rapidly and accurately process low power, high speed incoming analog signal components, the analog signal path must be free from the influences of biases and offsets, particularly DC biases which may manifest themselves, for example, as an offset in a conversion stage. Such an offset causes a reduction in the useful conversion range and can lead to signal clipping and other undesirable anomalies capable of disrupting signal detection, recovery, accuracy, and so on.
Still further, to take advantage of digital signal processing, and to improve overall accuracy and detection capability across the input range, any bias or offset must be compensated for prior to conversion. However, because a large number of devices are manufactured at once and due to process variances, not all circuits will have the same bias. It will be appreciated that in application specific integrated circuits (ASICs), analog sections of the circuit are extremely sensitive and can be affected differently by small variations in fabrication tolerances. To address these variances, calibration is usually necessary involving manual termination of the RF signal input stage by manually attaching a signal ground or other terminator to the input of a signal path. Such manual calibration is time consuming, expensive, and subject to human and systematic error and is therefore undesirable.
Still further, manual calibration methods ignore problems associated with bias drift caused by temperature variations occurring during operation and the like. When an operating environment experiences temperature variations the initial calibration may no longer be valid and can lead to poor reception, loss of information, and the like.
Thus it would be advantageous for a receiver to be capable of providing calibration during signal reception without the need for manual termination of the RF signal input stage. Still further, such calibration could be performed whenever necessary, such as periodically, when device operating temperatures rise, on demand, or the like.